1. Field of the Invention
The present invention relates generally to methods for forming patterned layers within microelectronic fabrications. More particularly, the present invention relates to methods for forming anti-reflective coating (ARC) layers which are employed for forming patterned reflective layers within microelectronic fabrications.
2. Description of the Related Art
Microelectronic fabrications are formed from microelectronic substrates over which are formed patterned microelectronic conductor layers which are separated by microelectronic dielectric layers.
As microelectronic fabrication integration levels have increased and microelectronic device and patterned microelectronic conductor layer dimensions have decreased, it has become increasingly important within microelectronic fabrications to form microelectronic device and patterned microelectronic conductor layers with enhanced linewidth control. Such enhanced linewidth control of microelectronic device and patterned microelectronic conductor layers when formed employing reflective microelectronic materials within microelectronic fabrications is typically effected by employing interposed between: (1) a reflective blanket microelectronic layer desired to be patterned to form a microelectronic device or patterned microelectronic conductor layer; and (2) a blanket photoresist layer from which is formed a patterned photoresist layer which in turn is employed in forming the microelectronic device or patterned microelectronic conductor layer from the reflective blanket microelectronic layer, a blanket anti-reflective coating (ARC) layer. Such blanket anti-reflective coating (ARC) layers are employed to attenuate standing wave photoexposure reflections which would otherwise provide for inhomogeneous photoexposure of the blanket photoresist layer.
While blanket anti-reflective coating (ARC) layers are thus desirable within the art of microelectronic fabrication for purposes of assisting in forming from blanket microelectronic layers formed of reflective materials microelectronic device and patterned microelectronic conductor layers with enhanced linewidth control, blanket anti-reflective coating (ARC) layers themselves are not formed entirely without problems within the art of microelectronic fabrication. In that regard, it is often important that blanket anti-reflective coating (ARC) layers be formed within microelectronic fabrications in a fashion such that they uniformly attenuate standing wave photoexposures of blanket photoresist layers formed upon those blanket anti-reflective coating (ARC) layers and thus in turn provide more uniform linewidth patterned photoresist layers which ultimately provide enhanced linewidth control of microelectronic devices and patterned microelectronic conductor layers formed employing those blanket anti-reflective coating (ARC) layers. Such a result often requires that a blanket anti-reflective coating (ARC) layer be formed with enhanced film thickness uniformity.
It is thus towards the goal that the present invention is directed.
Various methods and resulting microelectronic fabrication structures have been disclosed within the art of microelectronic fabrication for forming anti-reflective coating (ARC) layers with desirable properties within microelectronic fabrications.
For example, Chen et al., in U.S. Pat. No. 5,418,019, discloses a plasma enhanced chemical vapor deposition (PECVD) method for forming an anti-reflective coating (ARC) layer for use upon a silicon substrate layer within a microelectronic fabrication, where the anti-reflective coating (ARC) layer has: (1) enhanced anti-reflective properties in comparison with a single layer silicon nitride anti-reflective coating (ARC) layer formed employing a plasma enhanced chemical vapor deposition (PECVD) method; and (2) enhanced manufacturability in comparison with a bilayer magnesium difluoride/zinc sulfide anti reflective coating (ARC) layer formed employing a thermal evaporation method. The plasma enhanced chemical vapor deposition (PECVD) method employs forming upon the silicon substrate layer a silicon nitride layer having a refractive index of about 2.3, and then forming upon the silicon nitride layer a silicon oxide layer.
In addition, Tsukamoto et al., in U.S. Pat. No. 5,600,165, discloses a field effect transistor (FET) semiconductor integrated circuit microelectronic fabrication device whose gate electrode patterning is effected employing a silicon oxynitride anti-reflective coating (ARC) layer while simultaneously attenuating degradation of electrical properties of the field effect transistor (FET) semiconductor integrated circuit microelectronic device incident to hydrogen diffusion from the silicon oxynitride anti-reflective coating (ARC) layer into a gate dielectric layer of the field effect transistor (FET) semiconductor integrated circuit microelectronic fabrication device. The field effect transistor (FET) semiconductor integrated circuit microelectronic device is fabricated while effecting the foregoing result by employing interposed between the silicon oxynitride anti-reflective coating (ARC) layer and the gate dielectric layer a hydrogen permeation barrier layer.
Finally, McKee, in U.S. Pat. No. 5,804,088 discloses a method for forming microelectronic devices and patterned microelectronic layers of linewidth narrower than a minimum linewidth of a patterned photoresist layer formed from a blanket photoresist layer photoexposed with i-line photoexposure radiation. The method employs an intermediate layer formed interposed between a blanket target layer to be patterned and a patterned photoresist layer employed in patterning the blanket target layer, where the intermediate layer may provide: (1) anti-reflective coating (ARC) properties when forming the patterned photoresist layer from a corresponding blanket photoresist layer while employing i-line photoexposure radiation; (2) etch stop properties when forming an isotropically etched patterned photoresist layer from the patterned photoresist layer; and (3) etch residue liftoff properties for removing from a patterned target layer derived from the blanket target layer etch residues after etching patterned target layer to a linewidth dimension defined by the isotropically etched patterned photoresist layer.
Desirable in the art of microelectronic fabrication are additional methods and materials for forming anti-reflective coating (ARC) layers with enhanced film thickness uniformity.
It is towards that goal that the present invention is directed.